Abuse of alcohol creates enormous social and financial problems. An improved understanding of the molecular basis of alcohol intoxication is likely to improve our treatments for alcohol poisoning and withdrawal, and further our understanding of alcohol tolerance and addiction, the development of which is likely to be rooted in the acute effects of alcohol. The overall goal of this project is to identify molecular targets of alcohol that mediate the behavioral effects of the drug using the model organism, Caenorhabditis elegans. The level of conservation of the nervous system components in C. elegans and humans is such that the targets of alcohol found in C. elegans are likely to be present in the human nervous system. Given the link between acute alcohol response and predisposition to alcoholism, the human homologs of the genes identified in this study are likely to be valid candidates for genes that predispose an individual to alcoholism. The following specific aims describe the means by which these ethanol targets will be identified. 1. Isolate mutations affecting alcohol targets or regulators of those targets using forward genetics. The premise of this aim is that a mutation that eliminates a target of alcohol will display increased resistance. A behavioral screen of the progeny of randomly-mutagenized slo-1 mutant animals will be employed that is selective for mutants that display increased levels of resistance to the effect of alcohol on locomotion. Using a slo-1 mutation will ensure that the screen will identify targets of alcohol other than SLO-1. 2. Carry out behavioral and pharmacological characterization of the mutants and a detailed examination of their alcohol response across a variety of behaviors to provide insight into the nature of the mutant defect in the animals, as well as providing a means of prioritizing which of the mutants to study. 3. Positional map and clone the prioritized genes using a combination of genetic mapping and a candidate gene approach that will utilize RNA interference to test the effect of loss of function of candidates on alcohol sensitivity. 4. Determine the expression pattern of the resistance genes using green fluorescent protein. This aim along with Aim 2 will assist in defining a function for the genes (if not already known) and will provide a better understanding of the mechanism by which mutations in these genes result in ethanol resistance.